Thermal taster status associates with oral sensations elicited by wine

Backgrounds and Aims: Individual differences in the perception of wine flavour may contribute to variation in wine consumer behaviour. Two phenotypes shown to associate with the intensity of oral sensations elicited by simple solutions are thermal taster status (TTS) and responsiveness to the bitterant 6-n-propylthiouracil (PROP). Thermals tasters (TTs) perceive ‘phantom’ tastes when the tongue is thermally stimulated. Here, we investigate the effect of TTS and PROP responsiveness on the perceived intensity of oral sensations elicited by wine. Methods and Results: Two white (2008 Pinot Grigio, Italy and 2007 Gewürztraminer, Canada) and two red (2007 Valpolicella, Italy and 2007 Cabernet Sauvignon, Chile) wines were assessed by 20 TTs and 20 thermal non-tasters (TnTs). TTs rated the intensities of sweet, sour, bitter, astringent and overall flavour higher than TnTs, and males (17) tended to rate these sensations higher than females (23). Unexpectedly, PROP responsiveness was not associated with intensity ratings of oral sensations for any wine (P(r) > 0.05). Neither TTS, PROP responsiveness, nor gender was linked with liking scores of the wines. Conclusion: TTS may be an important determinant of individual differences in oral perception of wine. Significance of Study: Understanding how individuals differ in their perception of wine can assist with product development, formulation and marketing.     

Application of TCATA to examine variation in beer perception due to thermal taste status

Thermal taste status (TTS) describes a phenotype whereby some individuals experience a thermally-induced taste on thermal stimulation of the tongue (thermal tasters; TTs) and some do not (thermal non-tasters; TnTs). TTs experience a range of orosensations elicited by aqueous solutions and some beverages more intensely than TnTs. Whether this extends throughout ingestion duration is unknown, despite the fact that the evolution of flavour on the palate is a key component of consumer acceptance of food/beverages. We sought to use temporal-check-all-that-apply (TCATA) to determine how beer perception varies with TTS. A secondary aim was to investigate the effects of serving temperature and a concurrent auditory cue on TCATA responses and how these may interact with TTS. Forty-one female participants (21 TTs, 20 TnTs) were trained to identify seven dominant sensations elicited by a de-alcoholized beer (astringent, bitter, carbonation, fruity/hops, malty, sour, sweet). Beer samples were served in duplicate at either 6 °C or 21 °C with or without a concurrent auditory cue consisting of a sound clip of effervescence. TTs cited astringent and bitter more frequently than TnTs (p(F) ≤ 0.01), and the area under the curve (AUC) was greater for TTs for several sensations (p(t) < 0.05). Samples served at 6 °C had higher carbonation citation frequencies (p(F) < 0.001) and AUC at 0–30 s (p(t) < 0.001) and 30.1–60 s (p(t) < 0.05) than the warmer samples, with responses for astringent following a same pattern. AUC for carbonation and astringent varied within the sound conditions at 0–30 s (p(t) < 0.05). Overall, these results show that the ‘taste’ advantage of TTs extends to beer, and that temporal methods are needed to more fully describe consumer variation.     

PHENOLIC ACIDS IN BEERS AND WORTS

The total contents of phenolic acids measured by high-performance liquid-chromatography were 5–8 mg/litre in beers brewed in Ireland whereas 16–40 mg/litre were present in four other beers. In all beers the predominant phenolic acids were vanillic, p-coumaric and ferulic acids. Free phenolic acids were extracted from Emma barley grains and malt in very small amounts (15–28 mg/kg) but larger quantities (191 mg/kg) were released on mashing the malt. Little change occurred in the contents of phenolic acids on processing a lager wort through to the finished beer. Treatment with excess Polyclar AT removed astringent flavour and phenolic acids from an experimental ale but this flavour loss could not be accounted for by the adsorption of phenolic acids. The flavour threshold for a nine-component phenolic acid mixture in lager was between 50 mg/litre and 100 mg/litre.     

Phenotypic variation in oronasal perception and the relative effects of PROP and Thermal Taster Status

Individual variation in taste perception has long been investigated, particular in relation to PROP taster status (PTS). Recently, a new marker has been identified, Thermal Taster Status (TTS), whereby individuals are categorised as thermal tasters (TTs) or thermal non-tasters (TnTs) based on their ability to perceive taste solely from temperature stimulation. The aim of this study was to investigate the incidence of thermal tasters and relative effects of PTS and TTS on oronasal sensitivity across the whole perceptual range. Both detection thresholds (ASTM E679) and intensity measures at suprathreshold level (rated on gLMS) for stimuli from a range of modalities were determined from up to 124 subjects pre-screened for their PTS and TTS. For the detection threshold tests stimuli included tastants (sucrose, NaCl, caffeine), trigeminal stimuli (N-ethyl-2-isopropyl-5-methylcyclohexanecarboxamide (WS3) and capsaicin), and aromas (ethyl butyrate and isoamyl acetate). Tastants (sucrose, NaCl, citric acid and caffeine) plus capsaicin as a trigeminal stimulus were evaluated at suprathreshold level. No significant differences were found within either PTS or TTS groups at detection threshold level, with one exception; TTs had a lower threshold for sucrose (p < 0.05). At supra-threshold level, PROP supertasters (pSTs) and medium tasters (pMTs) rated stimuli higher than non-tasters, and a consistent trend was observed that TTs rated stimuli higher than TnTs, although only ratings for temperature (warm and cold) reached significance. Global analyses applied across each modality, showed that in general TTs rated gustatory and trigeminal modalities significantly higher than TnTs, whilst this was not the case for olfactory stimuli, indicating that the mechanism for increased perception for TTs may be located in the oral cavity. PTS and TTS were shown to be independent phenotypes, but interestingly, ANOVA revealed significant interactions between TTS and PTS across the three modalities. Most notably, within pMTs, TTs rated stimuli intensity higher than TnTs, while the opposite trend was observed for pSTs. The intensity advantage gained by thermal tasters appears to be more apparent for pMTs than the already highly sensitive pSTs.     

An overview of selected specialty beers: developments,challenges and prospects

The brewing industry has devoted much research effort into the development of new technologies and innovations for the expansion of the assortment of specialty beers in response to increased consumer demand. Specialty beers are more or less the catch‐all for beer styles, which do not fit into conventional beer categories and five types of specialty beers are of particular interest – low‐calorie beer, low‐alcohol or nonalcohol beer, novel‐flavoured beer, gluten‐free beer and functional beer. The selected beer types are technologically challenging to produce relative to the traditional approach of ingredient addition, yet offer special appeal to consumers from the perspective of health and flavour. Biological processes that make use of the equipment of a traditional brewery plant should be better exploited in comparison with nonbiological technologies such as thermal and membrane processes. Probiotic beer could be the specialty beer of the future in light of the increasing popularity of probiotics. These beers are reviewed in terms of developments, challenges and prospects.     

The Role of Malt and Hop Polyphenols in Beer Quality,Flavour and Haze Stability

Pilot‐scale brewing trials of a 12°P pale lager beer were conducted to look at the effect of a modified dose of hop and malt polyphenols on haze, flavour quality, and stability. Results confirmed that malt polyphenols, and particularly hop polyphenols, in the course of wort boiling, improved reducing activity values and the carbonyl content in fresh and stored beers. Hop polyphenols significantly increased reducing activity and decreased the formation of carbonyls (TBA value) in fresh and stored beer. Reduced content of malt polyphenols, combined with the use of hop CO₂ extract, caused an increase in the TBA value in beer. PVPP stabilized beers tended to be lower in reducing activity. Both malt and hop polyphenols affected the intensity of “harsh taste” in fresh beers and a significant influence from PVPP stabilization of beer was not observed. The staling degree of forced‐aged beers depended on the polyphenol content in the brewhouse. Both hop and malt polyphenols had a positive impact on flavour stability. PVPP treatment of beer had a positive effect on the flavour stability of heat‐aged beers. Polyphenols, especially hop polyphenols, slowed down flavour deterioration during the nine month storage period, but the primary effect was seen during the first four months of storage. Storage trials did not show any unambiguous effects for PVPP stabilization on beer flavour stability. Results confirmed the negative impact of malt and hop polyphenols on haze stability, and PVPP stabilization minimized differences in shelf life prediction values between beers prepared with the modified dose of polyphenols.     

Association of thermal taste and PROP responsiveness with food liking,neophobia, body mass index,and waist circumference

6-n-Propylthiouracil (PROP) responsiveness is a well-established index of individual variation in oral sensation that has a genetic basis and appears to predict food liking and consumption. More recently, thermal taster status (TTS), a new marker of individual variation in oral sensation was identified. Thermal tasters (TTs) perceive phantom tastes in response to lingual thermal stimulation, and are more responsive to orosensory stimuli than thermal non-tasters (TnTs). The association of TTS and PROP responsiveness with food liking, body mass index (BMI), waist circumference (WC), and neophobia was examined. One hundred and twenty-seven subjects rated liking of 332 food and beverage items, which included different preparations of foods, using a 7-point hedonic scale. TTS did not associate with BMI or WC, and contrary to previous studies, neither did PROP responsiveness. TnTs’ greater liking of cooked fruits and vegetables over TTs suggests that differences between TTS groups may be texturally driven. As expected, liking of bitter and fatty foods and cream was inversely related to PROP responsiveness.     

Supplementing hedonic and sensory consumer research on beer with cognitive and emotional measures,and additional insights via consumer segmentation

A consumer-based multivariate approach to the study of eight commercial beers (mass-produced, speciality and craft) was undertaken in New Zealand with ∼200 people. The beers spanned a wide range of sensory characteristics, from traditional lager and ale styles to high flavour impact beers with novel flavours (e.g. liquorice and rosemary) and less common styles (weisse and gose). These flavour differences were a larger driver of consumers’ hedonic/emotional/cognitive responses than alcohol content, which ranged from 0.5 to 7.2% alcohol by volume (ABV). The supplementation of hedonic and perceptual measures with emotional and cognitive variables resulted in a more detailed differentiation of products, which was further enhanced by consumer segmentation. In the rapidly evolving beer market, there is significant value in product-focused consumer research that delivers insights “beyond liking” and provide a deeper level of understanding about consumers’ product experiences. The research also contributed methodologically to the multivariate approach by considering pros and cons of study implementation aspects such as free-listing and ballot length. This will benefit future researchers in study planning and execution.     

Personality traits and bitterness perception influence the liking and intake of pale ale style beers

Bitterness is classically considered undesirable in foods and beverages. Yet, widespread commercial success of beers (like Bitters in the UK or IPAs in the US) indicate bitterness is desirable for some consumers. Here, we tested whether personality traits influence beer liking and intake. Under laboratory conditions, beer consumers (n = 109) rated liking and intensity of 2 pale ales and a lager, and intensity of two bitter solutions (quinine, Tetralone®). Participants also completed intake and personality questionnaires (Sensation Seeking, Sensitivity to Punishment and Reward, and Food Involvement). A liking ratio for each beer was calculated from each participant’s liking for that specific beer and their total liking for all beers. Participants were classified as weekly, monthly, or yearly pale ale consumers using intake data. Using intensity ratings, personality measures, and other parameters, hierarchical linear regression was used to predict liking ratios, and logistic regression was used to predict beer intake frequency. A significant interaction between Sensation Seeking and quinine bitterness (p = 0.03) was found for the liking ratio of a pale ale. The interaction revealed liking of the pale ale increased with Sensation Seeking but only if quinine bitterness was also high. Intake models showed increased odds of frequent pale ale intake with greater quinine bitterness and lower liking for lager beer. These data suggest liking and intake of pale ales is positively related to Sensation Seeking and bitter taste perception. Contrary to findings in other bitter foods and beverages, the high bitterness found in pale ales may be desirable for some consumers.     

The Contribution of 4‐Hydroxyfuranone Derivatives to the Aroma of Commercial Beers and Malts

Analysis of hot water extracts from a range of commercial malts showed that 2,5‐dimethyl‐4‐hydroxy‐3(2H)furanone (DMHF) varied from undetectable (lager malt) to 4.2 mg/litre (crystal malt), a concentration twenty‐six times the flavour threshold in water. 5‐Methyl‐4‐hydroxy‐3 (2H)furanone (MHF) was detected in all samples except one but was always well under its flavour threshold value. 2(or 5)‐Ethyl‐5(or 2)‐methyl‐4‐hydroxy‐3(2H)furanone (EMHF) was not detected in any of the samples. Fermentation of lager, ale and crystal malt extracts with an ale strain of yeast led to the appearance of EMHF in all cases as well as additional DMHF. The greatest increases in both compounds was with the ale malt. Both increases and decreases occurred in MHF concentration as a result of fermentation but final levels were always well below the flavour threshold value. Analysis of ten commercial beers found DMHF in all the samples and in five cases levels exceeded twice the flavour threshold value in beer with flavour units from 2.4 to 9.1. A flavour panel noted that in four of these cases the beer had a distinctly sweet/caramel aroma which is typical of DMHF. EMHF was undetectable in six samples, detectable, but unquantifiable, in three cases but at about 80% of the flavour threshold value in the remaining sample. MHF was found in all samples but at insignificant levels. The results show that DMHF is an important flavour compound in British ales and EMHF may make a contribution in a limited number of situations. The contribution of malt type, brewery processing and yeast strain in determining the concentration of the two 4‐hydroxyfuranones in beer remains uncertain.     

CAPRYLIC FLAVOUR AS A FEATURE OF BEER FLAVOUR

Caprylic flavour is part of the distinctive overall flavour of a large proportion of beers in trade. The flavour occurs in the majority of lager beers and in about 20% of ales. It is correlated with the levels of octanoic acid and decanoic acid present in beer. Lager yeasts (S. uvarum) tend to liberate larger amounts of these two fatty acids during fermentation than do ale yeasts (S. cerevisiae). The flavour significance of these acids has been determined by correlating the results of sensory and instrumental analyses and also by adding the purified acids to beer. Implications of these two methods for assessing the flavour significance of chemical constituents of a complex product are discussed.     

Physicochemical characterization of sahti,an ‘ancient’ beer style indigenous to Finland

Sahti, a strong, unhopped farmhouse beer flavoured with juniper, is still actively brewed in rural areas in Finland. Presented here is the first comprehensive analysis of the physical and chemical properties of this unique beer style. Twelve sahti samples from the southwest of Finland were analysed and, while properties varied, the beers generally had high levels of alcohol (mean = 7.9% ABV) and high residual extract (mean = 9.5°P). Foam stability was negligible, as is typical for the style, and glycerol concentrations at 3.1 – 4.7 g L^?1 were higher than in reference beers (commercial lager, wheat beer and porter). These features may be attributed to the very high gravity conditions employed in brewing sahti beers. Bitterness levels were relatively low (3–13 IBU) owing to the absence or moderate use of hops. All samples contained detectable levels of the clove‐like compound 4‐vinylguaiacol owing to the use of baker's rather than brewer's yeast for brewing. Concentrations of higher alcohols and esters were high, with many individual aroma compounds being above the normal flavour thresholds. Results have highlighted the uniqueness of this style of beer in comparison to commercially available beers and have contributed to our understanding of the reasons for the particular sensorial properties of this traditional beer style. Copyright © 2015 The Institute of Brewing & Distilling     

Analysis of flavour compounds in beer with extruded sorghum as an adjunct using headspace solid‐phase micro‐extraction and gas chromatography–mass spectrometry

Sorghum is a widely used adjunct that is used in the production of beer and increasingly affects beer flavour as the amount added increases. The aim of this work was to establish a simple, solvent‐free technique, without derivatization, to analyse flavours and typical volatile compounds present in extruded and unextruded sorghum beer, and to compare the flavour differences of the two types of beer. Headspace solid‐phase micro‐extraction gas chromatography–mass spectrometry was used to determine the flavours in the two beers and eight typical volatile compounds were quantified using GC. Forty‐five flavour compounds were identified and quantified in extruded white sorghum beer, while 31 flavour compounds were identified in unextruded white sorghum beer. Extruded or unextruded white sorghum can be used to produce ale beer, but the primary flavour content in the extruded white sorghum beer was higher than in the unextruded white sorghum beer. Copyright © 2016 The Institute of Brewing & Distilling     

DIFFERENTIATION OF ALE AND LAGER FLAVOURS BY PRINCIPAL COMPONENTS ANALYSIS OF FLAVOUR CHARACTERIZATION DATA

The application of principal components analysis to flavour characterization data has been examined by comparing and contrasting 32 beer samples. These comprised two samples of each of 16 brands of beer selected to represent 4 different types, contrasting ales and lager beers of two different strengths. Two-dimensional plots of results using the first two principal components as axes showed resolution of the four groups of beers and the close proximity of the majority of the duplicate samples. Differences between samples thus revealed are in accordance with known differences between the beer flavours.     

Flavour Instability of Pale Lager Beers: Determination of Analytical Markers in Relation to Sensory Ageing

Flavour changes of six Belgian pale lager beers were studied in order to estimate the importance of different parameters and reactions in relation to the ageing process. An attempt was made to link analytical data with sensory evaluation using multivariate statistical analysis. Partial least squares regression techniques (PLSR) were employed on the analytical and sensory data. As apparent from the PLSR model, significant indicators of lager beer ageing are aldehyde markers (especially total aldehydes, furfural, hexanal, 2‐methylpropanal, 2‐methylbutanal, and 3‐methylbutanal), cold and permanent haze, and beer colour. Conversely, compounds or parameters that load negatively in the PLSR model for beer ageing are trans‐isohumulones, cis‐isohumulones, total bitterness, the T/C‐ratio, polyphenolic markers (especially proanthocyanidins), the flavanoid content, and, to a lesser extent, the TB‐index and reducing power (TRAP). The integrated analytical‐sensorial methodology is proposed as a useful tool for evaluation of the flavour instability of pale lager beers.     

Determination of Prolamins in Beers by ELISA and SDS‐PAGE

Coeliac disease is triggered by exposure to the prolamin protein fraction of wheat, barley, or rye. The prolamin content of five lager beers and one wheat beer were analyzed by sodium dodecyl sulfate—polyacrylamide gel electrophoresis (SDS‐PAGE) and immunoblotting and seven lager beers and three wheat beers were analyzed by enzyme‐linked immunosorbent assay (ELISA). Most of the lager beers were made from barley and some had varying amounts of rice or corn as adjuncts. One of the beers was “gluten‐free”, having been produced from corn and buckwheat without barley. The lager beer samples were gel‐filtered before ELISA or SDS‐PAGE analysis. Prolamin proteins were found in all but one beer which was made of corn, rice and barley and which was not the “gluten‐free” beer. ELISA analysis was done using a commercially available gluten assay kit. For lager beers, a barley prolamin standard for ELISA was propanol‐extracted from barley malt instead of using the prolamin standard of the gluten assay kit. As expected, the wheat beers contained much higher amounts of prolamins than the lager beers. The samples were studied by SDS‐PAGE to identify different prolamin fractions. Proteins having a relative molecular mass in the range of 8000–17,000 and 38,000 and above were detected in immunoblotting by the prolamin sensitive antibody in the lager beers.     

Analytical‐Sensory Determination of Potential Flavour Deficiencies of Light Beers

Although currently light beers have a high market share in the US, this beer style is still not accepted on the European continent because light beers are considered watery, mainly on account of lack of mouthfeel. In this paper, the flavour quality, including flavour stability, of five commercial light beers was evaluated in comparison with their corresponding pilsner beers derived from the same breweries. Through detailed physico‐chemical and sensory evaluation, followed by multivariate data analysis, the fresh beers could be differentiated according to their origin (US or European) and beer style (light or pilsner). Potential flavour deficiencies of fresh light beers were determined as too much sweetness, lack of bitterness, and especially reduced fullness. As a result, the fresh light beers were less preferred than their corresponding pilsner. Upon ageing, the light beers were generally less flavour stable than their pilsner counterparts. This is mainly ascribed to increased sensory perception of cardboard and ribes staling flavours in most aged light beers. Nevertheless, based on detailed analytical/sensory investigation, it was clearly demonstrated that one of the light beers involved in this study showed enhanced flavour stability with respect to all other beers, including the pilsner beers.     

Influence of hop harvest date of the ‘Mandarina Bavaria’ hop variety on the sensory evaluation of dry‐hopped top‐fermented beer

To impart a special hop aroma to beer, dry‐hopping is a technique that is becoming more and more popular with commercial breweries. Nevertheless, until now little was known about the factors that influence the reproducibility (and consistent product quality) of dry‐hopping with flavour varieties. One factor that could influence the sensory impressions and aroma profile compositions of dry‐hopped beers is the hop harvest date. Therefore, to determine the effects of different harvest dates of the flavour variety ‘Mandarina Bavaria’ on the aroma of top‐fermented beer, laboratory‐scale dry‐hopping trials were performed. Besides tasting sessions of brewed beers, relative quantities of selected hop‐derived, as well as beer‐originated aroma compounds, were investigated by headspace–solid‐phase microextraction–gas chromatography–mass spectrometry. Duo–trio tests between the beers hopped with pellets of different harvest dates showed no significant differences (α = 0.05) between them. In addition, these beers had similar profiles in a five‐point profile tasting scheme. On the other hand, relative concentrations of some hop‐derived aroma compounds – especially myrcene, which is known to be able to contribute to beer flavour – increased corresponding to a later harvest date, while beer originated volatiles were not different between the beers. Analytical results combined with the results of sensory evaluations led to the conclusion that the harvest date of Mandarina Bavaria was not a dominant factor in the dry‐hopping aroma of top‐fermented beers. High amounts of fermentation by‐products are likely responsible for masking effects resulting in no sensory distinctness between the samples with different hop aroma compound concentrations. Copyright © 2016 The Institute of Brewing & Distilling